Associative acrylic thickening agent containing polyglycerols and its use to increase the open time of thin or thick films

ABSTRACT

The present invention relates to new acrylic associative thickening agents which, when polymerized in the presence of particular polyglycerols, ultimately result in an increase of the open time of the paint or of the thick coating in which they are in incorporated. By so doing, painters and applicators will have more time to work the paint layers gradually or to correct imperfections such as paint droplets, and traces of brushes and filling-knives.

REFERENCE TO PRIOR APPLICATIONS

This application claims priority to U.S. provisional application Ser.No. 61/561,029, filed Nov. 17, 2011; and to French patent application 1160004, filed Nov. 4, 2011, both incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to new acrylic associative thickeningagents which, when polymerized in the presence of particularpolyglycerols, ultimately result in an increase of the open time of apaint or of a thick coating in which they are in incorporated. By sodoing, painters and applicators will have more time to work the paintlayers gradually or to correct imperfections such as paint droplets, andtraces of brushes and filling-knives.

Additional objects, advantages and other features of the presentinvention will be set forth in part in the description that follows andin part will become apparent to those having ordinary skill in the artupon examination of the following or may be learned from the practice ofthe present invention. The advantages of the present invention may berealized and obtained as particularly pointed out in the appendedclaims. As will be realized, the present invention is capable of otherand different embodiments, and its several details are capable ofmodifications in various obvious respects, all without departing fromthe present invention. In this regard, the description herein is to beunderstood as illustrative in nature, and not as restrictive.

BACKGROUND OF THE INVENTION

In the field of water-based coatings, such as water-based paints, theopen time is the period during which the film of the moist paint or ofthe thick coating, once applied to a surface, can be reworked; it canthen be corrected, notably through new applications using a roller,brush or spatula, without surface defects appearing at the end.

In the remainder of the application, the term “open time” of a paintwill be used; this expression makes reference to the open time of thethin wet film of the paint, or of the thick wet film of the renders,roughcast paints or other thick coatings, etc., after they have beenapplied on to a medium.

It is understood that in formulations of water-based paints in whichwater evaporation is a rapid phenomenon (compared to paints containingsolvents which can have high boiling points), reducing the open time isan important issue.

With this regard, specific additives, known as “open-time extenders”,have been developed by the skilled man in the art, the first of thesebeing ethylene glycol and glycol ethers, mentioned as prior art in“Development of low VOC additives to extend the wet edge and open timeof aqueous coatings” (Progress in Organic Coatings, 2011, 72 (1-2), pp.102-108). However, these have the disadvantage that they are solvents,which the water-based paints industry has decided not to use, preferringto focus on VOC-free formulations.

Natural waxes have also been developed (see documents WO 2001036550 A 1,WO 2001036549 A1, WO 2008022828 A1 and WO 2009138304 A1): but theyrequire a more complex application method, since they must be meltedbefore being incorporated in the paint formulation; in addition, ifinsoluble residues remain these can seriously affect the stability ofthe final paint composition.

Finally, surfactants are currently most in favour (see documents U.S.Pat. No. 5,154,918 A1, US 2011091408 A1 and WO 2011/071510 A1): theseare easy to apply, and are VOC-free compounds which enable the open timeof water-based paints to be increased, notably through the repulsioneffects caused by their hydrophobic groups between the latex particles,which commensurately reduces the phenomenon of water evaporation overtime, consequently increasing the open time of the wet paint film (WO2011/071510 A1).

Independently of their properties, these additives “which increase theopen time” constitute an additional ingredient of the water-based paintformulation: the skilled man in the art is then faced with the problemsof storage and handling relating to every new product used in itsformulation. In addition, it is well known that every new additive caninteract with the other constituents of the formulation, and affect someof the final properties of the paint film. The skilled man in the artmust then, if applicable, adjust his formulation, taking these negativeimpacts into account.

For this reason it was sought to increase the open time of the paints,by means of additives which have already been made indispensable inthese formulations, but which are known to contribute other properties.This is notably the case of particular products called “associativethickening agents”.

In water-based paints, thickening agents enable the rheology of theformulations to be controlled, both during their manufacture, and duringtheir transport and storage, or during their application. The widevariety of practical constraints in each of these stages relates to amultiplicity of different rheological properties.

Nevertheless, the requirement of the skilled man in the art can besummarized as to obtain an effect of the thickening of a water-basedpaint, both for reasons of stability over time, and for a possibleapplication of the paint to a vertical surface, lack of splashing duringuse, etc. For this reason the additives which contribute to thisregulation of the rheological properties have been designated by theterm “thickening agents”.

It has been well known for many years that natural thickening agentsmade of the HEC (hydroxy ethyl cellulose) type help increase the opentime. Reference may notably be made, for example, to the technical formsof the products of the Natrosol™ type, sold by the company Aqualon™.However, the thickening properties of these products are only moderate.

The skilled man in the art then considered thickening agents known as“associative” thickening agents. These are water-soluble polymers havinginsoluble hydrophobic groups. Such macromolecules have an associatingcharacter: when introduced into water, the hydrophobic groups tend toassemble in the form of micellar aggregates. These aggregates are linkedtogether by the hydrophilic parts of the polymers: a three-dimensionalnetwork is then formed which causes the viscosity of the medium to beincreased.

The functional mechanism and the characteristics of the associativethickening agents are now well known and described, for example in thedocuments “Rheology modifiers for water-borne paints” (Surface CoatingsAustralia, 1985, pp. 6-10) and “Rheological modifiers for water-basedpaints: the most flexible tools for your formulations” (Eurocoat 97,UATCM, vol. 1, pp. 423-442).

And it is now established that certain associative thickening agentsenable the open time of paint formulations into which they areintroduced to be increased (“Control of rheology of water-borne paintsusing associative thickeners”, Progress in Organic Coatings (1999), 35(1-4), 171-181). This document teaches that an associative thickeningagent of a polyurethane or HEUR (Hydrophobically modified Ethylene oxydeURethane) nature, having a determined molecular weight, effectivelyenables the open time of a water-based paint to be increased.

However, associative thickening agents of the HEUR type have thedisadvantage that they are insoluble in water, for commerciallyacceptable dry extracts: use must therefore be made of surfactants,which complicates their application. The skilled man in the arttherefore logically turns to the other major class of acrylicassociative thickening agents: HASEs (Hydrophobically Alkali SolubleEmulsions). These can be defined in terms of the monomers whichconstitute them: the first uses a (meth)acrylic acid base, the second isan ester of this acid, and the third is an associative hydrophobicmonomer. As examples, it is notably possible to cite European patentapplications EP 0 577 526 A1, EP 1 778 797 A1, EP 2 108 007 A1, EP 2 114378 A1 and EP 2 303 982 A1, and French patent applications FR 2 950 061A1 and FR 2 956 862 A1.

However, to our knowledge there is no method in the state of the artable to give HASE-type associative thickening agents an ability toincrease the open time of the paint formulations in which they areincorporated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventors have developed, among other things disclosed herein, newHASE-type thickening agents, and a new method for manufacturingHASE-type thickening agents, using polyglycerols as “polymerizationsurfactants”. The latter expression means that the surfactants are usedduring one of the steps of synthesis of the associative thickeningagent. Conversely, “formulation surfactants” are used afterpolymerization of the thickening agent, notably in order to use thefinished product obtained after polymerization in water.

In connection with the method of manufacture of the HASE thickeningagents according to the invention, it is demonstrated that the resultingproducts enable the open time of a paint to be increased appreciably. Asolution resolving the problem of increasing open time, without using anadditional additive which causes logistical constraints, is thusavailable. HEUR-type associative thickening agents, formulation of whichis more constrictive to attain commercially attractive dry extracts, areavoided, and it is demonstrated that open times equivalent to thoseobtained with an HEC are obtained, but with greater thickening power.

The use of surfactants during polymerization of an acrylic associativethickening agent is already known: it is notably described in documentWO 2009 019225 A1. Furthermore, it is already known to use glycerolduring the same type of synthesis, as disclosed in document WO 98 06757A1. Nevertheless, nothing described or suggested that the use ofpolyglycerols, as polymerization surfactants, was likely to lead to newHASE-type associative thickening agents which would be particularlyeffective in increasing the open time in water-based paints.

An object of the invention is a method to manufacture an associativethickening agent by polymerization, in an aqueous dispersion, in thepresence of surfactants other than the compounds listed in d) below:

-   -   a) of at least one monomer which is (meth)acrylic acid, and        preferentially methacrylic acid,    -   b) of at least one monomer which is an ester of (meth)acrylic        acid, and preferentially ethyl acrylate,    -   c) of at least one monomer having a hydrophobic group,        wherein d) at least one polyglycerol of formula (I) is used        during the polymerization

where R designates hydrogen, or an ester group functionalized by analkyl group having 8 to 22 carbon atoms, or an alkyl group having 8 to22 carbon atoms, and preferentially an alkyl group having 8 to 22 carbonatoms.

This method is also wherein a first step of introducing into watercompounds d) and the surfactants other than the compounds d) isaccomplished, followed by a second step of increasing the temperature ofthe medium, followed by a third step of introducing polymerizationinitiators, and then monomers, possibly added in combination with waterand surfactants other than compounds d).

The method is also wherein the surfactants other than compounds d)preferably include those chosen from among the anionic surfactants, andpreferentially from among sodium dodecyl sulphate, dioctyl sodiumsulfosuccinate, sodium dodecylbenzenesulfonate, the non-ionicsurfactants, and preferentially the ethers of fatty alcohols and ofpolyoxyethylene glycol, the esters of polyoxyethylene glycol and theblends of these surfactants.

The method is also wherein the mass % of surfactants other thand)/polymer is preferably between 1% and 5%.

This method is also wherein the polymerization preferably uses, as a %by weight, compared to the total weight of the associative thickeningagent:

-   -   a) 20% to 60% by weight of at least one monomer which is        (meth)acrylic acid, and preferentially methacrylic acid,    -   b) 40% to 80% of at least one monomer which is an ester of        (meth)acrylic acid, and preferentially ethyl acrylate,    -   c) 0.5% to 25% of at least one monomer having a hydrophobic        group,    -   d) 0.1% to 10% by weight of at least one polyglycerol of formula        (I),

where R designates hydrogen, or an ester group functionalized by thealkyl group, having 8 to 22 carbon atoms, or an alkyl group having 8 to22 carbon atoms, and preferentially an alkyl group having 8 to 22 carbonatoms, where the sum of the percentages a), b), c) and d) is equal to100%.

The method is also wherein the monomer containing at least onehydrophobic group preferably has the general formulaR—(OE)_(p)-(OP)_(q)—R′, where:

-   -   m and n designate integers of less than or equal to 150, at        least one of which is non-zero, with preferentially q=0 and        0<p<80,    -   OE and OP designate respectively ethylene oxide and propylene        oxide,    -   R designates a polymerisable group, and preferentially the        methacrylate or methacrylurethane group,    -   R′ designates a hydrophobic group having at least 6 and at most        36 carbon atoms.

The method is also wherein the associative thickening agent preferablyhas an average molecular mass by weight of between 20,000 g/mole and1,000,000 g/mole, as measured by GPC.

Another object of the present invention lies in an associativethickening agent, such as the one obtained by the method according tothe present invention.

Another object of the present invention is the use of such a thickeningagent, as an agent to improve the open time of an aqueous formulation oran adhesive, where the aqueous formulation is preferentially awater-based paint, a roughcast paint or a render.

Another object of the present invention is an aqueous formulation oradhesive containing the thickening agent above, where the aqueousformulation is preferentially a water-based paint, a roughcast paint ora render.

The following examples will enable the present invention to be betterapprehended, without however limiting its scope.

EXAMPLES

In each of the following examples, the molecular masses of theassociative thickening agents are determined by GPC.

Synthesis of the thickening agents is well known to the skilled man inthe art, and reference may be made in particular to the variousdocuments cited in the application as background concerning HASEtechnology.

The paints are formulated using the methods well known to the skilledman in the art. All the Brookfield™ viscosities of the paintformulations are measured at 25° C.

Finally, the open time of the paints is determined using 2 techniques,depending on whether a thin film or a thick film of moist paint isapplied.

When a thin film is concerned, the open time is measured by means of atest undertaken in a controlled atmosphere (climate-controlled room),where the time when the first layer is no longer diluted is determinedon a freshly applied film, by successive repeats.

In concrete terms, in a climate-controlled room with the temperature setat 23±1° C. and with 50% relative humidity, 240 μm of a paint havingcured for at least 24 h is applied using a multi-layer applicator on ablack Leneta card (wet abrasion card). The chronometer is then startedand this card is attached with adhesive tape to a Placoplatre™ plate; acheck is made that the length of the adhesive strip is equal to thewidth of the card.

After 15 min. one begins to sweep the surface of the still-wet film witha “30” brush from left to right over a 3 cm strip; a proportion of thepaint is thus moved with the brush to the unpainted surface on theright.

This operation is undertaken every minute, taking care to use a brushwhich is always dry, and always to apply the same pressure.

The sweeping is stopped when it is no longer possible to move paintrightwards. From that point forth, the Leneta card moves when the brushmoves over it: this is the instant when the film can no longer bediluted; consequently the brush no longer slides. This instant is theopen time.

When a thick film is concerned, the open time is determined indirectlyby means of a spreading test.

In a climate-controlled room with a temperature set at 23±1° C. and withhygrometry controlled at 50±5%, a determined quantity in terms of shapeand volume of the product to be tested is applied on a Placoplatre™plate using a jig.

This jig consists of a trapezoid-shaped stainless steel frame (with nobackground) of a thickness ranging from 0 to 14 mm, with a large baseB=72 mm, a small base b=58 mm and a height h=150 mm. The depth is 0 mmfor B and 14 mm for b and varies in linear proportion. This jig isattached to the Placoplatre™ plate, with the larger base upward.

The product is placed inside until the jig is filled completely. Thesurplus product is removed by levelling-off using a wall scraper ofwidth greater than B, so as to position the product perfectly and suchthat it perfectly follows the shape of the jig.

The latter is then removed (mould release), taking care to leave nothingon the edges of the frame. The product settles to a greater or lesserdegree during the drying time. The spreading amplitude is measured inthe widest location 24 hours after application. It is expressed as apercentage of the additional spreading proportion relative to the widthof the jig. It is considered that the larger the amplitude the greaterthe open time of the thick film.

Example 1

This example illustrates the synthesis and use of the variousassociative thickening agents according to the invention (presence ofpolyglycerol during the synthesis), or outside the invention (withoutadditives, with glycerol used during the synthesis or as a formulationagent, with polyglycerol added as a formulation surfactant).

The use in question occurs in a water-based paint, the constitution ofwhich is given in table 1; the figures indicate the mass in grams ofeach constituent.

TABLE 1 Water 294.0 Ammonia 31% 2.0 Ecodis 40 (Coatex™) 3.0 Acticide MBS(Thor™) 2.0 Byk™ 34 (Byk™) 1.0 TiONA™ 568 (Cristal™) 41.0 Durcal 5(Omya™) 328.0 Omyacoat™ 850 OG (Omya™) 215.0 Axilat™ DS 910 (Hexion™)82.0 Butyl diglycol 20.0 Thickening agent subject to testing   12.0 * *the value of 12 grams is equal the mass of an emulsion containing 30% bydry weight of polymer (except for test n° 4 which uses 9.0 grams by dryweight of a commercial thickening agent in powder form).Test n° 1:

This test illustrates a HASE thickening agent outside the invention,polymerized with a conventional surfactant.

This thickening agent results from the synthesis, expressed as a % byweight of the monomers, of:

-   -   a) 37.4% of methacrylic acid,    -   b) 54.3% of ethyl acrylate,    -   c) 8.3% of a monomer of formula (I), in which:        -   R designates the methacrylate group,        -   q=0, p=25,        -   where R′ designates the hydrophobic group resulting from oxo            alcohol having 16 carbon atoms.

In a 1-litre reactor, 485.4 grams of bipermuted water and 6.66 grams ofsodium dodecyl sulphate and 11.5 g of non-ionic surfactant, which isisotridecyl alcohol condensed with 3 molecules of ethylene oxide, areweighed. The base of the tank is then heated to 72° C.±2° C.

During this time, a pre-emulsion is prepared by weighing the followingin a beaker:

-   -   149 grams of bipermuted water,    -   2.33 grams of sodium dodecyl sulphate,    -   111.33 grams of methacrylic acid;    -   161.45 grams of ethyl acrylate,    -   24.6 grams of macromonomer of formula (I).

The mass of non-ionic surfactant therefore accounts in this case for3.7% of the total mass of the manufactured polymer.

0.95 grams of ammonium persulphate is then weighed, diluted in 10 gramsof bipermuted water for the first catalyst, and 0.095 grams of sodiummetabisulphite diluted in 10 grams of bipermuted water for the secondcatalyst. When the base of the tank is at the required temperature bothcatalysts are added, and polymerization is effected for 2 hours at 76°C.±2° C., with simultaneous addition of the pre-emulsion. The pump isrinsed with 20 grams of bipermuted water, and is fired for 1 hour at 76°C.±2° C. Finally it is cooled to ambient temperature, and the dispersionobtained in this manner is filtered.

Test n° 2:

This test illustrates a HASE thickening agent outside the invention,polymerized with a conventional surfactant.

This is the same thickening agent as that of test n° 1, in which thenon-ionic surfactant has been replaced, in mass terms, by nonylphenolcondensed with 4 molecules of ethylene oxide.

Test n° 3:

This test illustrates a HASE thickening agent outside the invention,polymerized with a conventional surfactant.

This is the same thickening agent as that of test n° 1, in which thenon-ionic surfactant has been replaced, in mass terms, by a surfactantsold by the company Clariant™ under the name Polyglykol™ B11/150

Test n° 4:

This test illustrates an HEC-type thickening agent outside the inventionwhich is Natrosol™ 250 HR (Aqualon™); it is used as a reference.

Test n° 5:

This test illustrates a thickening agent outside the invention,formulated in water with the introduction of glycerol afterpolymerization.

The thickening agent is that of test n° 1, polymerized according to thetechnique described in test n° 1.

In the final solution with 30% by dry weight of active matter, 3% by dryweight of glycerol from the company Oleon™ relative to the dry weight ofpolymer is introduced.

Test n° 6:

This test illustrates a thickening agent outside the invention,formulated in water with the introduction of polyglycerol afterpolymerization.

The thickening agent is that of test n° 1, polymerized according to thetechnique described in test n° 1.

In the final solution with 30% by dry weight of active matter, 3% by dryweight, relative to the dry weight of polymer, of polyglycerol-3 offormula (I), with R═H, and n=3 sold by the company Solvay™, isintroduced.

Test n° 7:

This test illustrates a thickening agent outside the invention,formulated in water with the introduction of polyglycerol afterpolymerization.

The thickening agent is that of test n° 1, polymerized according to thetechnique described in test n° 1.

In the final solution with 30% by dry weight of active matter, 3% by dryweight, relative to the dry weight of polymer, of hydrophobicpolyglycerol, which is Chimexane™ NB of formula (I) with R═C₁₈H₃₅ andn=2 sold by the company Chimex™, is introduced.

Test n° 8:

This test illustrates a thickening agent outside the invention,polymerized in the presence of glycerol.

The thickening agent is that of test n° 1, polymerized according to thetechnique described in test n° 1, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, byglycerol from the company Oleon™.

Test n° 9:

This test illustrates a thickening agent according to the invention,polymerized in the presence of polyglycerol-3, which is the one used intest n° 6.

The thickening agent is that of test n° 1, polymerized according to thetechnique described in test n° 1, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, by thepolyglycerol-3 of test n° 6.

Test n° 10:

This test illustrates a thickening agent according to the invention,polymerized in the presence of Chimexane™ NB, which is the one used intest n° 7.

The thickening agent is that of test n° 1, polymerized according to thetechnique described in test n° 1, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, by theChimexane™ NB of test n° 7.

For each of these tests the Brookfield™ viscosities were determined at25° C., at 10 and 100 revolutions per minute, at instant t=1 day(μ_(10 IJ), μ_(100 IJ)), where instant t=0 is the time of manufacture ofthe paint.

The open time of the paint expressed in minutes using the protocol setout in the preamble for a thin film is also determined, at instant t=1day.

The results are shown in table 2.

TABLE 2 Test n° 1 2 3 4 5 REFerence OI OI OI REF OI Outside InventionINvention μ_(10 lJ) (mPa · s) 6,600 6,500 6,800 5,500 5,600 μ_(100 lJ)(mPa · s) 2,600 2,700 2,800 2,000 2,200 open time (min.) 33 33 33 35 34Test n° 6 7 8 9 10 REFerence OI OI OI IN IN Outside Invention INventionμ_(10 1J) (mPa · s) 6,200 6,400 9,100 10,500 5,000 μ_(100 1J) (mPa · s)2,700 2,800 3,600 3,800 2,100 open time (min.) 34 34 34 36 37 Tests n° 1to 3 demonstrate that the choice of a habitual polymerization surfactanthas no influence on the open time.

When glycerol or polyglycerols are used as the formulation surfactant(tests n° 5 to 8), the influence on the open time is minimal.

Test n° 4 demonstrates that a modified cellulose does indeed enable theopen time to be increased; a substantial mass of it must however be used(9 grams of active product, compared to 3.6 grams of active product ofthe 12 grams of emulsion at 30% dry extract) to obtain levels ofviscosity comparable to those obtained with HASE-type emulsions.

Only tests n° 9 and 10 (use of polyglycerols during the polymerizationstep) lead to a significant increase of the open time, with unchangedthickening efficacy. The greatest open time is obtained for test n° 10,which is the preferential variant of the invention.

Example 2

This example illustrates the synthesis and use of different associativethickening agents, according to the invention (presence of polyglycerolduring the synthesis), or outside the invention (without addition ofpolyglycerol during the synthesis).

The use occurs in a water-based paint, the constitution of which isgiven in table 3; the figures indicate the mass in grams of eachconstituent.

TABLE 3 Water 281.0 Ammonia 31%  2.0 Ecodis 40 (Coatex™)  3.0 ActicideMBS (Thor™)  2.0 Byk™ 34 (Byk™)  1.0 TiONA 568 (Cristal™)  41.0 Durcal 5(Omya™) 328.0 Omyacoat™ 850 OG (Omya™) 215.0 Axilat™ DS 910 (Hexion™) 82.0 Butyl diglycol  20.0 Thickening agent subject to testing  24.0 * * the 24 grams are the mass of an emulsion containing 30% bydry weight of polymerTest n° 11:

This test illustrates a HASE thickening agent outside the invention,polymerized with a conventional surfactant.

This thickening agent results from the synthesis, expressed as a % byweight of the monomers, of:

-   -   a) 33.7% of methacrylic acid,    -   b) 59.4% of ethyl acrylate,    -   c) 6.9% of a monomer of formula (I), in which:        -   R designates the methacrylate group,        -   q=0, p=25,        -   R′ designates the branched hydrophobic group with 16 carbon            atoms.

In a 1-litre reactor, 288 grams of bipermuted water, 3.5 grams of sodiumdodecyl sulphate and 11.5 g of non-ionic surfactant, which isisotridecyl alcohol condensed with 3 molecules of ethylene oxide, areweighed. The base of the tank is then heated to 72° C.±2° C.

During this time, a pre-emulsion is prepared by weighing the followingin a beaker:

-   -   285 grams of bipermuted water,    -   3.5 grams of sodium dodecyl sulphate,    -   102.06 grams of methacrylic acid;    -   180 grams of ethyl acrylate,    -   21 grams of macromonomer of formula (I),    -   0.64 grams of dodecylmercaptan.

The mass of non-ionic surfactant therefore accounts in this case for3.6% of the total mass of the manufactured polymer.

0.95 grams of ammonium persulphate is then weighed, diluted in 10 gramsof bipermuted water for the first catalyst, and 0.095 grams of sodiummetabisulphite diluted in 10 grams of bipermuted water for the secondcatalyst. When the base of the tank is at the required temperature bothcatalysts are added, and polymerization is effected for 2 hours at 76°C.±2° C., with simultaneous addition of the pre-emulsion. The pump isrinsed with 20 grams of bipermuted water, and is fired for 1 hour at 76°C.±2° C. Finally it is cooled to ambient temperature, and the dispersionobtained in this manner is filtered.

Test n° 12:

This test illustrates a thickening agent according to the invention,polymerized in the presence of polyglycerol-4 sold by the companySolvay™.

The thickening agent is that of test n° 11, polymerized according to thetechnique described in test n° 11, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, by thepolyglycerol-4 of test n° 6.

Test n° 13:

This test illustrates a thickening agent according to the invention,polymerized in the presence of Chimexane™ NB.

The thickening agent is that of test n° 11, polymerized according to thetechnique described in test n° 11, except that the polymerizationsurfactant has been substituted, in mass terms, by the Chimexane™ NB.

Test n° 14:

This test illustrates a HASE thickening agent outside the invention,polymerized with a conventional surfactant.

This thickening agent results from the synthesis, expressed as a % byweight of the monomers, of:

-   -   a) 35.57% of methacrylic acid,    -   b) 52.43% of ethyl acrylate,    -   c) 12% of a monomer of formula (I), in which:        -   R designates the methacrylate group,        -   q=0, p=30,        -   R′ designates the hydrophobic group consisting of 12 carbon            atoms and derived from ethoxylation of an oxo alcohol            consisting of 12 carbon atoms.

In a 1-litre reactor 485.4 grams of bipermuted water and 6.66 grams ofsodium dodecyl sulphate and 11.5 g of a surfactant sold by the companyClariant™ under the name Polyglykol™ B11/150 are weighed. The base ofthe tank is then heated to 72° C.±2° C.

During this time, a pre-emulsion is prepared by weighing the followingin a beaker:

-   -   149 grams of bipermuted water,    -   0.33 grams of sodium dodecyl sulphate,    -   105.8 grams of methacrylic acid;    -   155.9 grams of ethyl acrylate,    -   35.7 grams of macromonomer of formula (I).

The mass of surfactant therefore accounts in this case for 3.7% of thetotal mass of the manufactured polymer.

0.95 grams of ammonium persulphate is then weighed, diluted in 10 gramsof bipermuted water for the first catalyst, and 0.095 grams of sodiummetabisulphite diluted in 10 grams of bipermuted water for the secondcatalyst. When the base of the tank is at the required temperature bothcatalysts are added, and polymerization is effected for 2 hours at 76°C.±2° C., with simultaneous addition of the pre-emulsion. The pump isrinsed with 20 grams of bipermuted water, and is fired for 1 hour at 76°C.±2° C. Finally it is cooled to ambient temperature, and the dispersionobtained in this manner is filtered.

Test n° 15:

This test illustrates a thickening agent according to the invention,polymerized in the presence of polyglycerol-4 of the company Solvay™.

The thickening agent is that of test n° 14, polymerized according to thetechnique described in test n° 14, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, bypolyglycerol-4.

Test n° 16:

This test illustrates a thickening agent according to the invention,polymerized in the presence of Chimexane™ NB sold by the companyChimex™.

The thickening agent is that of test n° 14, polymerized according to thetechnique described in test n° 14, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, by theChimexane™ NB.

For each of these tests the Brookfield™ viscosities were determined at25° C., at 10 and 100 revolutions per minute, at instant t=1 day(μ_(10 IJ), μ_(100 IJ)), where instant t=0 is the time of manufacture ofthe paint.

The open time of the paint expressed in minutes using the protocol setout in the preamble for a thin film is also determined, at instant t=1day.

The results are shown in table 4.

TABLE 4 Test n° 11 12 13 REFerence OI IN IN Outside Invention INventionμ_(10 lJ) (mPa · s) 7,700 8,500 8,200 μ_(100 lJ) (mPa · s) 2,700 2,9003,000 open time (min.) 30 32 34 Test n° 14 15 16 REFerence OI IN INOutside Invention INvention μ_(10 lJ) (mPa · s) 7,300 7,000 7,100μ_(100 lJ) (mPa · s) 3,000 2,400 2,500 open time (min.) 29 31 33

If tests n° 12 and 13 are compared with test n° 11, and tests n° 15 and16 with test n° 14, it can be ascertained that the use of polyglycerolsaccording to the invention, during the polymerization step, enables theopen time to be increased appreciably, without affecting the thickeningpower.

The longest open times are obtained for tests n° 13 and 16, which arethe preferential variant of the invention.

Example 3

This example illustrates the synthesis and use of different associativethickening agents, according to the invention (presence of polyglycerolduring the synthesis), or outside the invention (without addition ofpolyglycerol during the synthesis).

The use in question occurs in a water-based thick coating, theconstitution of which is given in table 5; the figures indicate the massin grams of each constituent.

TABLE 5 Water 258.5 Ammonia 31%  2.5 Ecodis 40 (Coatex™)  3.0 Mergal K6N 2.0 Nopco™ NDW  1.0 Durcal 130 (Omya™) 380.0 Durcal 2 (Omya™) 200.0Axilat™ DS 910 (Hexion™)  40.0 Thickening agent subject to testing  14.0 * * the value of 14 grams is equal the mass of an emulsioncontaining 30% by dry weight of polymer (except for test n° 18 whichuses 9.0 grams of Natrosol in powder form).Test n° 17:

This test illustrates a HASE thickening agent outside the invention,polymerized with a conventional surfactant.

This thickening agent results from the synthesis, expressed as a % byweight of the monomers, of:

-   -   a) 37.1% of methacrylic acid,    -   b) 52.9% of ethyl acrylate,    -   c) 10% of a monomer of formula (I), in which:        -   R designates the methacrylate group,        -   q=0, p=35,        -   R′ designates the branched hydrophobic group having 20            carbon atoms.

In a 1-litre reactor, 473.55 grams of bipermuted water and 4.42 grams ofsodium dodecyl sulphate and 11 g of non-ionic surfactant, which isisotridecyl alcohol condensed with 3 molecules of ethylene oxide, areweighed. The base of the tank is then heated to 72° C.±2° C.

During this time, a pre-emulsion is prepared by weighing the followingin a beaker:

-   -   116 grams of bipermuted water,    -   108.14 grams of methacrylic acid;    -   153.75 grams of ethyl acrylate,    -   29 grams of macromonomer of formula (I).

The mass of non-ionic surfactant therefore accounts in this case for3.6% of the total mass of the manufactured polymer.

0.95 grams of ammonium persulphate is then weighed, diluted in 10 gramsof bipermuted water for the first catalyst, and 0.095 grams of sodiummetabisulphite diluted in 10 grams of bipermuted water for the secondcatalyst. When the base of the tank is at the required temperature bothcatalysts are added, and polymerization is effected for 2 hours at 76°C.±2° C., with simultaneous addition of the pre-emulsion. The pump isrinsed with 20 grams of bipermuted water, and is fired for 1 hour at 76°C.±2° C. Finally it is cooled to ambient temperature, and the dispersionobtained in this manner is filtered.

Test n° 18:

This test illustrates an HEC-type thickening agent outside the inventionwhich is Natrosol™ 250 HR (Aqualon™); it is used as a reference.

Test n° 19:

This test illustrates a thickening agent according to the invention,polymerized in the presence of Chimexane™ NB sold by the companyChimex™.

The thickening agent is that of test n° 17, polymerized according to thetechnique described in test no 17, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, by theChimexane™ NB.

Test n° 20:

This test illustrates a thickening agent according to the invention,polymerized in the presence of Chimexane™ NC sold by the companyChimex™.

The thickening agent is that of test n° 17, polymerized according to thetechnique described in test n° 17, except that the non-ionicpolymerization surfactant has been substituted, in mass terms, by theChimexane™ NC of formula (I) with R═C₁₈H₃₅ and n=4.

Test n° 21:

This test illustrates a thickening agent according to the invention,polymerized in the presence of Chimexane™ NB sold by the companyChimex™.

The thickening agent is that of test n° 17, polymerized according to thetechnique described in test n° 17, except that the polymerizationsurfactant has been substituted (twice the mass) by the Chimexane™ NB.

For each of these tests the Brookfield™ viscosities were determined at25° C., at 10 and 100 revolutions per minute, at instant t=1 day(μ_(10 IJ), μ_(100 IJ)), where instant t=0 is the time of manufacture ofthe thick coating.

The open time of the thick coating using the protocol set out in thepreamble for a thick film is also determined, at instant t=1 day.

The results are shown in table 6.

TABLE 6 Test n° 17 18 19 20 21 REFerence OI REF IN IN IN OutsideInvention INvention μ_(10 lJ) (Pa · s) 109 83 103 88 112 μ_(100 lJ) (Pa· s) 27 30 26 23 30 open time (% of extension) 60 120 103 95 122

These results demonstrate that the thickening agents according to theinvention (tests n° 19 to 21) enable the open time to be increased,relative to the reference, whilst retaining a satisfactory thickeningpower.

Test n° 21 even enables the open time as obtained with the referenceproduct according to test n° 18 to be improved (but with only 4.2 gramsof active product, compared to 9.0 grams for the HEC-type product).

Preferred embodiments of the invention, described herein such that oneof skill in this art can make and use them, include:

1—A method for manufacturing an associative thickening agent comprisingpolymerizing, in an aqueous dispersion, in the presence of one or moresurfactants other than polyglycerols of formula (I) below, the followingmonomers:

-   -   a) at least one monomer which is (meth)acrylic acid,    -   b) at least one monomer which is an ester of (meth)acrylic acid,        and    -   c) at least one monomer having a hydrophobic group,        in the presence of d) at least one polyglycerol of formula (I):

where R designates hydrogen, or an ester group functionalized by analkyl group having 8 to 22 carbon atoms, or an alkyl group having 8 to22 carbon atoms.

2—A method according to Embodiment 1, conducted as follows:

introducing into water said at least one polyglycerol of formula (I) andthe one or more surfactants other than polyglycerols of formula (I),followed by increasing the temperature of the medium, followed byintroducing at least one polymerization initiator, and then monomers a),b) and c), optionally added in combination with additional water andadditional surfactants other than polyglycerols of formula (I).

3—A method according to Embodiment 1, wherein the one or moresurfactants other than polyglycerols of formula (I) are chosen fromanionic surfactants, non-ionic surfactants, and blends of thesesurfactants.

4—A method according to Embodiment 1, wherein the mass % of the one ormore surfactants other than polyglycerols of formula (I)/a)−d) is 1%-5%.

5—A method according to Embodiment 1, wherein the associative thickeningagent is obtained by polymerizing, as a % by weight, relative to thetotal weight of the associative thickening agent:

-   -   a) 20% to 60% by weight of at least one monomer which is        (meth)acrylic acid,    -   b) 40% to 80% of at least one monomer which is an ester of        (meth)acrylic acid, and    -   c) 0.5% to 25% of at least one monomer having a hydrophobic        group, in the presence of    -   d) 0.1% to 10% by weight of at least one polyglycerol of formula        (I)        where the sum of the percentages a), b), c) and d) is equal to        100%.

6—A method according to Embodiment 1, wherein the monomer containing atleast one hydrophobic group has the general formulaR—(OE)_(p)-(OP)_(q)—R′, where:

-   -   m and n designate integers of less than or equal to 150, at        least one of which is non-zero,    -   OE and OP designate respectively ethylene oxide and propylene        oxide,    -   R designates a polymerizable group,    -   R′ designates a hydrophobic group having at least 6 and at most        36 carbon atoms.

7—A method according to Embodiment 1, wherein the associative thickeningagent has an average molecular mass by weight of 20,000 g/mole-1,000,000g/mole, as measured by GPC.

8—A method according to Embodiment 3, wherein the anionic surfactantsare selected from the group consisting of sodium dodecyl sulphate,dioctyl sodium sulfosuccinate, sodium dodecylbenzenesulfonate, andmixtures thereof, and the non-ionic surfactants are selected from thegroup consisting of ethers of fatty alcohols and of polyoxyethyleneglycol, esters of polyoxyethylene glycol, and mixtures thereof.

9—A method according to Embodiment 1, wherein a) is methacrylic acid andb) is ethyl acrylate.

10—A polymeric associative thickening agent, which is the polymerobtained by the method according to Embodiment 1.

11—An aqueous formulation, comprising water and the polymericassociative thickening agent according to Embodiment 10.

12—The aqueous formulation according to Embodiment 11, wherein theaqueous formulation is selected from the group consisting of awater-based paint, a roughcast paint and a render.

13—A method, comprising adding the polymeric associative thickeningagent of Embodiment 10 to another material or formulation.

As used herein the term (meth)acrylic means methacrylic and acrylic, andsupports both terms. As used herein the terms composed of, contains,containing, and terms similar thereto, when referring to theingredients, parts, reactants, etc., of a composition, component, etc.,mean, in their broadest sense, “includes at least” (i.e., comprises) butalso include within their definition all those gradually restrictedmeanings until and including the point where only the enumeratedmaterials are included (e.g., consisting essentially of and consistingof).

The above written description of the invention provides a manner andprocess of making and using it such that any person skilled in this artis enabled to make and use the same, this enablement being provided inparticular for the subject matter of the appended claims, which make upa part of the original description. As used herein, the phrases“selected from the group consisting of,” “chosen from,” and the likeinclude mixtures of the specified materials. The term “mentioned” notesexemplary embodiments, and is not limiting to certain species. As usedherein the words “a” and “an” and the like carry the meaning of “one ormore.” When a polymer is referred to as comprising a monomer, themonomer is present in the polymer in the polymerized form of the monomeror in the derivative form of the monomer. However, for ease of referencethe phrase comprising the (respective) monomer or the like is used asshorthand.

All references, patents, applications, tests, standards, documents,publications, brochures, texts, articles, etc. mentioned herein areincorporated herein by reference. Where a numerical limit or range isstated, the endpoints are included. Also, all values and subrangeswithin a numerical limit or range are specifically included as ifexplicitly written out.

The above description is presented to enable a person skilled in the artto make and use the invention, and is provided in the context of aparticular application and its requirements. Various modifications tothe preferred embodiments will be readily apparent to those skilled inthe art, and the generic principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the invention. Thus, this invention is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein. In thisregard, certain embodiments within the invention may not show everybenefit of the invention, considered broadly.

1. A method for manufacturing an associative thickening agent comprisingpolymerizing, in an aqueous dispersion, in the presence of one or moresurfactants other than polyglycerols of formula (I) below, the followingmonomers: a) at least one monomer which is (meth)acrylic acid, b) atleast one monomer which is an ester of (meth)acrylic acid, and c) atleast one monomer having a hydrophobic group, in the presence of d) atleast one polyglycerol of formula (I):

where R designates hydrogen, or an ester group functionalized by analkyl group having 8 to 22 carbon atoms, or an alkyl group having 8 to22 carbon atoms.
 2. A method according to claim 1, conducted as follows:introducing into water said at least one polyglycerol of formula (I) andthe one or more surfactants other than polyglycerols of formula (I),followed by increasing the temperature of the medium, followed byintroducing at least one polymerization initiator, and then monomers a),b) and c), optionally added in combination with additional water andadditional surfactants other than polyglycerols of formula (I).
 3. Amethod according to claim 1, wherein the one or more surfactants otherthan polyglycerols of formula (I) are chosen from anionic surfactants,non-ionic surfactants, and blends of these surfactants.
 4. A methodaccording to claim 1, wherein the mass % of the one or more surfactantsother than polyglycerols of formula (I)/a)−d) is 1%-5%.
 5. A methodaccording to claim 1, wherein the associative thickening agent isobtained by polymerizing, as a % by weight, relative to the total weightof the associative thickening agent: a) 20% to 60% by weight of at leastone monomer which is (meth)acrylic acid, b) 40% to 80% of at least onemonomer which is an ester of (meth)acrylic acid, and c) 0.5% to 25% ofat least one monomer having a hydrophobic group, in the presence of d)0.1% to 10% by weight of at least one polyglycerol of formula (I) wherethe sum of the percentages a), b), c) and d) is equal to 100%.
 6. Amethod according to claim 1, wherein the monomer containing at least onehydrophobic group has the general formula R—(OE)_(p)-(OP)_(q)—R′, where:m and n designate integers of less than or equal to 150, at least one ofwhich is non-zero, OE and OP designate respectively ethylene oxide andpropylene oxide, R designates a polymerizable group, R′ designates ahydrophobic group having at least 6 and at most 36 carbon atoms.
 7. Amethod according to claim 1, wherein the associative thickening agenthas an average molecular mass by weight of 20,000 g/mole-1,000,000g/mole, as measured by GPC.
 8. A method according to claim 3, whereinthe anionic surfactants are selected from the group consisting of sodiumdodecyl sulphate, dioctyl sodium sulfosuccinate, sodiumdodecylbenzenesulfonate, and mixtures thereof, and the non-ionicsurfactants are selected from the group consisting of ethers of fattyalcohols and of polyoxyethylene glycol, esters of polyoxyethyleneglycol, and mixtures thereof.
 9. A method according to claim 1, whereina) is methacrylic acid and b) is ethyl acrylate.
 10. A polymericassociative thickening agent, which is the polymer obtained by themethod according to claim
 1. 11. An aqueous formulation, comprisingwater and the polymeric associative thickening agent according to claim10.
 12. The aqueous formulation according to claim 11, wherein theaqueous formulation is selected from the group consisting of awater-based paint, a roughcast paint and a render.
 13. A method,comprising adding the polymeric associative thickening agent of claim 10to another material or formulation.